Control system for oil well pumps



Dec. 8, 1953 M. v, LONG ET AL GONTROL SYSTEM FOR OIL WELL PUMPS 2 Sheets-Sheet 1 Filed Dec. 26, 1951 Yew: and

smer Power Saunas FIGUZE- 5 Manual 5+op 5wi+cl1 Dec. 8, 1953 M. v. LONG ET AL 2,661,697

CONTROL SYSTEM FOR OIL WELL PUMPS Filed Dec. 26, 1951 2 Sheets-Sheet 2 FIGURE 4- HGURE 2 lnvcnror: MN. Long Y ECSChnc'uder Patented Dec. 8, 1953 CONTROL SYSTEM FOR OIL WELL PUMPS Marion V. Long and Frederick Carl Schneider, Berkeley, Calif., assignors to Shell Development Company, Emeryville, Califi, a corporation of Delaware Application December 26, 1951, Serial No. 266,366

10 Claims.

This invention. relates to a system for the efficient production of oil wells and pertains more particularly to an automatic system for the starting and stopping of well pumps.

In many wells, especially during the later stages of their exploitation, the quantity of fluid entering the borehole from the formation is often less than that which can be readily handled by the pumping equipment, that is, the volumetric capacity of the pumping equipment installed at the well is such that a sustained operation thereof results in pumping the well 01? or dry. Under these conditions, it is usual to produce such wells by intermittent pumping, so that the fluid is permitted to accumulate in the borehole during pump shut-down periods, and is exhausted from the well during alternate pump operation periods.

Such intermittent operation of the well pumping equipment may be controlled. either manually, whereby the pump is started and stopped by hand for each operating period, or automatically, whereby the pump is started and stopped at predetermined set intervals by a time-responsive mechanism, such as an electrically or spring driven clock.

The disadvantages of manual, pump control methods, iIlVOlVlIlg the time-consuming task for a pump operator to visit a great number of wells, as well as the hazards of the human element, are obvious. The main disadvantage of most automatic time-responsive mechanisms is that they are adjusted to shut off and stop the pump after a certain time interval. If the time interval is not accurately determined for each well, the pumping period may be prematurely out oii at a time when considerable oil remains in the borehole, thus lowering the efficiency of the pumping operations, or the pumping period may be cut off only long after theborehole has been pumped substantially dry, thus increasing the wear on the pumping equipment and wasting power.

Additionally, many automatic pump control mechanisms employ a swinging or reciprocating check valve in the flow line containing the production fluid. The movement of the check valve gate is utilized to actuate the pump control mechanism. However, oil, as it is produced from a well, often contains considerable quantities of sand, paraffin or asphaltic materials which rapidly tend to Clog the check valve, and the associated pump control mechanism soon becomes inoperative.

While there are many devices, such as safety switches, well known to the art which are used for shutting down a well pumping installation in the event of failure of some piece of equipment in the installation, they are not adapted to shut down the pumping installation when the well has been pumped dry. When safety switches are used for this purpose, they are normally mounted on the walking beam of a pump and reciprocate therewith. In the event that the sucker rod string to the pump breaks, or any rod, link, pitman, cable or belt between the pump and the pump engine fails, the safety switch shuts oh" the engine when actuated by excessive or accelerated .rovement oi the oscillating walking beam.

Since these safety switches operate only when the motion of the pumping mechanism acce1er' ates or becomes irregular or eccentric, they cannot be used to shut ofi a pumping mechanism which continues to operate with a regular motion and at a constant speed even after the well is pumped dry. Additionally, due to the nature and use of the switches, they are never provided with means for being reset automatically but must be reset manually after the pumping mechanism has been repaired.

It is, therefore, an object of the present invention to provide a control system for automatically shutting down a well pumping mechanism when the Well has been pumped dry and for automatically starting the pumping mechanism again after a predetermined time interval.

A further object of this invention is to provide a control system for automatically shutting down a well which has been pumped dry, said system being adapted to automatically reset itself and stop the well pumping mechanism again after each pumping interval.

Another object of invention is to provide a control system for automatically shutting down a well pumping mechanism when any part of said mechanism is, caused to vibrate after the well has been pumped dry.

A further object of the present invention is to provide a control system for automatically shutting down a well pumping mechanism when any part of the well installation (e. g., production tubing, well head closure, Christmas tree, polished rod stufling box, etc.) is caused to vibrate after the fluid level in the well has been lowered to a point adjacent the well pump.

A still further object of this invention is to provide an automatic well shut-oh control system of simple construction havin a minimum number of moving parts and being adapted to give continuous service over long periods of time without special attention.

It is also an object of the present invention It is also an object of this invention to provide a well-pumping control system wherein the duration of the pumping period is automatically adjusted to the amount of fluid available for pumping from a well during said pumping period.

Another object of this invention is to provide a system wherein each pumping period may be started either by hand or by an automatic timeresponsive device, and is terminated by an automatic device responsive to well conditions.

These and other objects of this invention will be understood from the following description taken with reference to the attached drawing, wherein:

Figure 1 is a diagrammatic sketch illustrating the component parts of the present system;

Figures 2 and 4 are views, partly in cross section, of the controller device of the present system;

Figure 3 is detail of Figure 1 showing the connection between the polished rod and the horsehead of the pumping mechanism;

Figure 5 is a diagrammatic sketch illustrating a circuit for the present system;

Figure 6 is a wiring diagram of the combined relay and starter unit of Figure 5.

As shown in Figure 1, a pump (not shown) located in well I is actuated in a well-known manner by means of a polished rod 6 (Figure 3) secured to the top of a sucker rod string H, the

Well fluid lifted through production tubing 4 to the surface being directed to storage through pipe l2. The top of the well I0 is closed by any suitable type of closure means 2 well known to the art which is provided with a seal or stuffing box 3 through which the polished rod can move.

The horsehead of the pumping mechanism is secured to the sucker rod string H by means of the polished rod 6, a polished rod clamp I and cables or wire lines 8 and 9, as shown in Figure 3.

The sucker rod string I! is reciprocated in the 1 well by the oscillating motion of a walking beam |3, which is driven, through a pitman |4, crank I5 and speed reducing mechanism IE, by a prime mover l1 such as an electric motor receiving its power through leads Ill and I9. It is understood that any suitable type of motor or engine may be used as the prime mover ll, such, for example as a gas or gasoline engine having its energizing ignition current supplied through leads l8 and IS.

The control circuit of the pump motor I1 may comprise a power source 23, a suitable electrical interlock relay or motor starter in the power line to the motor, a periodically actuated control switch 2| and a controller device 21 which con- 3 caused to vibrate when the fluid level in the well has been lowered below the top of a Well pump of the reciprocating-piston type. For purposes of the claims appended hereinbelow, the term "pumping installation is employed to include both the pumping mechanism (walking beam,

weight 34.

sucker rod string, polished rod, etc.) and the well equipment through which the fluid is pumped.

Control switch 2| of the controller device 21 is normally open, being adapted to be closed by a time-responsive device such as an electric or spring driven clock mechanism 24 of any desired type. For simplicity, this mechanism is shown in Figure l as comprising a rotating wheel or disc 25 provided with a segment 26 adapted to close the switch 2| by contact therewith. It will be seen that the time at which the switch 2| is closed and opened can be accurately pre-set or controlled by suitably adjusting the speed of rotation of the disc 25 and/ or the size of the segment 26. Switch 2| may be also operated manually, if desired.

The controller device 21 is basically a simple system comprising a mass mounted on a spring which exerts an upward force against the mass at all times. The controller may be provided with a damping system, preferably a viscous damping system, as will be described in detail hereinbelow. As shown in Figure 2, the controller device 21 comprises a cylindrical casing 30 closed at the lower end by a cap 3| and at the upper end by a cap 32. The caps 32 and 3| are preferably secured in a screw-threaded manner to the casing 30. Suitable means are provided for securing the controller 21 to one of the moving parts of the pumping installation. Preferably the controller 21 is secured to the polished rod 6 by means of a mounting bracket or .clamp 33.

A cylindrical mass or weight 34 is mounted for sliding movement within the casing 30 above a compression spring 35 which exerts sufficient force to maintain the weight 34 at its uppermost position within the casing 30. An electrical switch is mounted within the casing 30 in a manner such as to be actuated by movement of the weight 34. In the design shown in Figure 2, a silver electrical contact and conductor terminal 33 is socured, as by screw or force fitting, into the top of an insulator plug 31 which is in turn screwthreaded into the top of the weight 34.

An insulated electrical lead 38, of sufficient length to allow free movement of the weight 34 within the casing 30, is connected between contact-terminal 36 and a conductor terminal 39 mounted in an insulator support-block 40. The block 40 is fixedly positioned within the casing 30 between the top of the casing and a shoulder 4| formed within the inner wall of the cap 32. If needed, gaskets 42 and 43 may be inserted between the block 40 and casing 30 and between the casing 30 and plate 3|, respectively, to make the casing fluidtight.

A rod 44 of suitable conducting material is screw-threaded axially down through the insulator block 40 so that a silver contact 45, secured to the bottom of the rod 44, is in face-to-face contact with contact-terminal 33. The rod 44 is preferably of sufficient length so that it can be adjustably screwed up or down in the block to adjust the force exerted by the spring 35 on the It is realized that the spring force exerted on the weight 34 may be varied in any other suitable manner, as by adjustably screwing the bottom plate 3| on the casing 30 to a diflerent position.

The brass terminal rod 44 maybe provided with a lock nut 46 for fixedly anchoring the rod 44 at a predetermined position in the block 40, Th lock nut 46 is fitted with a screw 50 which serves as a terminal for one lead 5| of an electrical conductor cable 52. The other lead 53 of the cable '5 52 is afiixed-to the upper end of the conductor terminal 39 which extends upward through the top of the insulator block 40. The cable 52 is led out through any suitable opening 54 in the wall. of said cap, said opening being preferably closed by a rubber bushing 55 surrounding the cable 52 and being held in place by a connector cap 56.

As previousl described, the casing 40 may be made fluidtight by gaskets 42 and 43 to form damping means for the spring-mounted weight 34. Thus, if air fills the casing 40, movement of the weight therein is slowed somewhat by airdamping. Preferably, the casing is substantially or completely filled with a viscous fluid such as oil. In order to fill the casing with oil, the bottom plate 3| may be provided with a removable plug 60. If thecasing 40 is to be completely filled with an oil, an expansion chamber may be provided within the casing to compensate for changes in volume of the oil with changes in temperature. One form of expansion chamber may comprise a raised annular flange 6! formed on or welded to the inner wall of the bottom plate 3 l. The flange Bl forms a chamber 62 which is closed by a flexible diaphragm 63 secured across the top of the flange by an anchoring washer B4 and screws 55. If air damping of the mass 3 iis provided, the mass or weight 34 may be solid with the air being allowed to leak from one side of the weight to the other through the narrow clearance between the weight 34 and the inner wall of the casing 38. When the casing 30 is substantially filled with an oil to provide viscous dampin of the movable weight 34, one or more ports or fluid passageways 56 are drilled longitudinally through the weight, :1

or in the direction in which the weight moves.

Check valve means, of any suitable design such as ball-type, falling-gate, etc., are preferably provided in the fluid passageways 66 to permit the flow of liquid through said passageways in one direction only. One simple design of a check valve may comprise a flexible piece of rubber t8 fastened to the top of the weight 34 by a screw 69 so that the piece of rubber covers the openingof passageway 65. Thus, as fluid passes up the passageway it forces the rubber valve F58 upward allowing fluid to escape readily into the chamber above the weight 34. As the weight attempts to rise the valve 68 falls or is forced over the upper end of passageway 55 to close it effectively against the passage of fluid. Fluid returning to the chamber 68 below the weight 34 has to leak slowly through the small clearance between the weight 34 and the inner wall of the casing 30.

Another design. for the controller device of the present invention is illustrated in Figure 4. The casing together with its bottom plate 3|, top cap 32 and spring are similar to those shown in Figure 2. The mass or slida-ble weight II is beveled at any suitable angle so as to actuate a mercury-type switch 72. The end of the switch 12 containing its contacts (not shown) is fixedly mounted in a guard bracket 73 which is in turn pivotally fastened to the casing 30 by means of a pin 14. It may be seen that with the spring 35 urging the weight H against the mercury switch 12, the top beveled surface of the weight ll tilts the pivoted mercury switch at an angle so that the mercury 75 therein flows to the lower end of the switch bridging the contacts therein and thus closing the switch. As the weight ii is moved downward away from the switch the mercury therein flows to the other end of the switch thus breaking the contact in a manner well known to the art. The guard bracket 13 may 6 extend under the mercury switch 12, as at It, to protect the switch from contact with the mass 1 I.

As shown in Figures 2 and 4, the controller device 21 (Figure 1) may take man forms. In each case the controller device 2'! comprises means responsive to vibrations of the element of the well installation or the pumping mechanism on which it i mounted.

A reciprocating string of sucker rods 1 l is normally operated at a constant frequency (strokes per minute) with a simple periodic motion when there is a positive head of fluid above the pistontype pump (not shown) in the well borehole. However, when the fluid level in the borehole drops to a point where the pump barrel is not completely filled with well fluid, the descending pump piston strikes the surface of the liquid in the pump barrel with considerable shock so that there is superimposed upon the normal sinusoidal acceleration pattern of the sucker rod string an additional acceleration caused by this shock. The pump piston and. associated elements of the pumping installation are subjected to repeated shocks as long as the pump continues to run L and the surface of liquid in the pump cylinder at the time is within the limits of the pump piston stroke.

The additional acceleration, caused by the pump piston striking the surface of the well liquid when the well is pumped dry, may be very small in some cases and quite considerable in others depending upon various factors such as depth of well, size of pumping equipment used, speed of pumping, etc. Vibration measurements were made on several pumping installations, both on a moving element such as the polished rod and a stationary element such as the well head, to study the acceleration, velocity and displacement imposed on elements of the installations when an actuated pump is not producing fluid. On one well the maximum acceleration of the sucker rod string was .7 8 G (where G equals acceleration of gravity) when fluid was being pumped and 1.81 G when the well was pumped dry. On another well the acceleration was 0.08 G when pumpin fluid and .6? G when pumped dry. On these wells the acceleration was about 2 and 8 times greater, respectively, when the pumps were pumping a dry Well. On another well installation the acceleration increased only about or from .984 G to 1.03 G when pumping fluid and pumping dry. On the other hand when measurements were taken on a well head the acceleration increased about 20 times, or from .008 to .15 when pumpin fluid and pumping dry. Yet, on Wells exhibiting only small measurable accelerations and even on wells having very little change in acceleration, the present system was found to be sufliciently sensitive to such small accelerations or changes therein tc shut down the pumping mechanism when the fluid level is lowered.

The abnormal accelerations imposed on the sucker rod string, walking beam, polished rod, well head, etc, while the well pump continues to operate at a constant reciprocating rate, is utilized bythe present well shut-oil system to stop the well-pumping mechanism. Prior to installing the controller on the polished rod for reciprocation therewith, or on the stationary well head, the force exerted by the spring 35 (Fig ure 2) is adjusted to a value suiiicient to main tain the weight 3 in its uppermost position with in the casing 30 whereby the electrical contacts 36 and remain together thus keeping the pump circuit closed, thereby maintaining normal pumping operation.

With the controller switch formed by contacts 35 and 45 closed, the pump may be started manually or automatically at any time when the timeresponsive device 24 (Figure 1) closes switch 2| sending current to the energizing coil 95 of the interlock relay 20 which is energized and closes the normally-open switches 96, 91 and 98 to send current to the pump motor H. The motor l1 reciprocates the pumping mechanism and the controller 21 when attached thereto. When the switch 2| of the time-responsive device 24 opens, the energizing coil 95 of relay 21! receives current through switch 96 which remains closed. After a period the well is pumped substantially dry and the level of the liquid in the well borehole is lowered until the cylinder of the well pump is no longer filled between each pump stroke.

When the level of the well fluid is lowered below the upper limit of the pump stroke, the piston of the well pump strikes the surface of the liquid in the cylinder of the pump during each stroke causing a shock that is transmitted up the sucker rod string and the production tubing to the pumping mechanism and the control mechanism at the top of the well. Even though the speed of the pumpin mechanism drive unit is normally governor-controlled so that the pumping mechanism continues to reciprocate at the same frequency, the additional accelerations superimposed by the shock of the pump piston hitting the surface of the well fluid are sufilcient to actuate the controller device 21.

When the shock wave is transmitted from the sucker rod string (Figure 1) to the controller 21 on the downstroke of the pump, the movable weight 34 (Figure 2) within the controller casing 33 is forced downward against the action of the spring 35 causing the electrical contacts 36 and 45 to part thus breaking the flow of current through the controller 21. The normal flow of current is through lead 5|, terminal 50, looking nut, down rod 44, across contacts 45 and 36, up

lead 38, through terminal post 39 to lead 53 and out cable 52.

The opening of contacts 36 and 45 causes the coil 95 of relay 2|] (Figure 1) to become deenergized allowing the spring-loaded switches 95,

91 and 98 to drop out and break the flow of current to the pump motor IT. This stops the motor I! at once and it does not start again until it is started manually or by the time-responsive starting mechanism 24 which closes switch 2| after a predetermined period. started at any time after the spring 35 has returned the weight 34 to its origin position with contacts 38 and 45 again closed, thereby resetting the controller 21. starting mechanism 24 may be of a design to hold the switch 2| closed for several minutes when the pump is first started. Thus, in the event that gas lock or other conditions causes the controller 21 to open its contacts and attempt to de-energize the relay 20 when there is fluid in the well to be pumped, the relay 2!! would remain energized and the pump would continue to operate.

The controller illustrated in Figure 4 operates in a similar manner. As a shock wave causes the weight 1| to move down in the casing 30, the mercury-type switch 12 and its bracket [3 pivot about pin 14 so that the switch 12 tilts downward causing the mercury pool therein to flow to the other end of the switch and away from the con- The motor may be The segment 26 of the tacts therein, thus stopping the flow of current therethrough.

As previously stated, the casing 30 is filled with oil and the weight 34 (Figure 2) is provided with passageways 66 when viscous damping is desired. The frequency selective properties of the mass, spring and viscous damping system employed in this device make it possible to take advantage of the amplification characteristics at or near the region of resonance of the system. The present system is preferably provided with a controller having a damping ratio less than 1.0. The system damping ratio can be adjusted by varying the diameter or throughput capacity of the fluid passages or by adjusting the viscosity of the oil. The system will operate when the damping ratio is anywhere between .01 and 1.5 or higher. If the damping ratio is too high the sensitivity of the controller is reduced to a point where it may become inoperative. n the other hand, if the damping ratio is too low the system becomes too sensitive to random vibration or other transient excitation, i. e., small shocks imposed on the system by coulomb and/or static friction during the normal operation of the pumping mechanism.

The present controller 21 comprising a mass, spring and viscous damping system may be represented mathematically by a simple second order difierential equation. When the proper parameters for such a system are chosen, they will display typical resonance conditions. Such a system may be tuned at or near its resonance frequency thereby making the controller frequency-selective and vastly increasing its sensitivity at or near its frequency. The damped natural frequency of the system can be readily adjusted by varying the spring constant and/or the mass. The mass 34 and spring 35 can be adjusted so as to respond to the accelerations of any part of the pumping installation which are caused by the pounding of the pump when the well has been pumped dry. These accelerations may vary from one well to another by as much as from .01 and G, where G is the acceleration of gravity.

When the controller casing 30 is filled with a fluid such as oil to form a viscous damping system, the movement of the weight 34 (Figure 2) within the casing is slowed down as it is necessary for the oil to flow through restricted fluid passageways 66 from chamber 68 to chamber as the weight moves downward, and in the opposite direction when the weight rises again.

When certain types of relays are used for relay in the circuit shown in Figure 1, the contacts of said relay 2!! do not drop out and lock out if the circuit is only momentarily opened by contacts 3E and 45 (Figure 2) parting when the weight 34 is forced toward the bottom of the casing. Hence, in order to keep the contacts 36 and 45 of the controller apart for more than a second, the system is provided, in addition to viscous damping, with valve means 68 for closing the fluid passageways 66. The valves allow the fluid to pass readily therethrough when the weight 34 descends in the casing 30, but shuts the passageways so that the fiuid has to slowly leek around the weight 34 when the spring returns the weight to close contacts 36 and 45. The slow return of this weight 34 allows the contacts 36 and to remain open long enough to insure the positive opening and lock out of the interlock relay 20 (Figure 1).

In some cases the shock imposed on the controller 21 of the present system may be so slight that, while the mass or weight 34 is moved downward a small increment, the movement is not sufficient to part the contacts 36 and 45 of the controller shown in Figure 2 or to tilt the mercurytype switch 72 of the controller shown in Figure 4. At such times the check valves 68 (Figures 2 and 4) operate in the following manner to open the contacts. After the well has been pumped dry and a slight shock is transmitted to the controller 21, the weight 34 contained therein moves downward a fraction of an inch at which time the valves 68 close preventing the immediate rise of the weight 34. On each subsequent stroke of the pump the weight is again moved down an other fraction of an inch. This continues until the weight has moved down enough to allow contacts 36 and 45 (Figure 2) to open orswitch I2 (Figure 4) to tilt. In either case, the present controller is capable of receiving and accumulating the acceleration forces until the sum'of several successive accelerations creates sufiicientforce to move the weight 34 down until contacts 36 and 45 part or switch 12 (Figure 4) tilts.

While the present controller 21 is shown as having a spring positioned on the bottom plate 3| for supporting the weight 34 thereon, it is realized that the spring could also be a tension spring secured to the insulator block 40 for holding the weight 34 in its uppermost position with the contacts 36 and in contact witheach other.

It is also to be understood that instead of the present system employing air or viscous damping, damping means utilizing the magnetic or electromagnetic. principle could be employed. For example, in the design of the controller device shown in Figure 2, the passageways 66 and/or the valves68 may be omitted from a Weight 34 which has been magnetized so that the north and south poles of the magnet are at or near the top and bottom of said weight. If the casing 30 is then made of a conducting material such as copper, a magnetic damping effect is imposed on the weight 66 as it moves axially within the casing 30. The relative motion of the magnetic weight 34 moving along the axis of the conducting casing 30 produces a current within the casing 30 which sets up a secondary magnetic field opposing that of the magnetic weight34. The opposition of these two magnetic fields produces a force along the axis of the casing 30 and weight 34 which opposes the initial motion of the magnetic weight 34.

Many other control circuits may be used with the present system. For example, instead of employing a relay 20 and a spring-driven clock mechanism 24 shown in the circuit of Figure 1, a single unit comprising a combinedrelay and electrical starting mechanism 80 may be used. One form of such a unit is shown in detail in Figure 6. a Y

The combined relay and starter 80 comprises an electrically driven starting device 8| having a rotating sector 82 for closing switch 83 in the circuit with a pull-in coil 84. The present system may also be started by closing the normally-open start switch 85. The unit is provided with a pair of switches 86 and 81 which are mechanically linked together so that one is closed while the other is open. The unit also includes a hold-in coil for-holding in switch 88 when energized and a pair of transformers 89 and 90.

With switch 81 closedQasillustrated in-Figure 6, the circuit to the starting device 8| is closed energizing said device causing sector 82 to rotate slowly and close switch 83 after a pre-determined 10 time, say 4 hours. The closing of switch 83 energizes coil 84 which pulls in switches 85 and 81, closing switch 86 to energize the pump motor H and holding coil 88 and opening switch 87 to de-energize the starter 85, thus opening switch 83 to de-energize the pull-in coil lit. Preferably, a spring-loaded starter is used which returns to its original setting when de-energized. With switch 8% closed the pump motor i? and the holding coil 88 remain energized until the stop switch is opened or the switch in the controller 2'1 (Figure 5) opens. On de-energizing the holding coil 88, spring-loaded switch 86 snaps open and switch 31 closes to energize the starter 8i again. The relay and starter unit may also contain a time delay mechanism for maintaining the pump circuit closed for a predetermined period, say, one minute, after the switch in the controller 27 opens. Thus, if the controller 27 was actuated accidentally before the Well had been pumped dry, the pump would continue to operate.

It is to be realized that the present controller device can also be mounted on hydraulic well pumping mechanisms which include a piston and cylinder arrangement for reciprocating the sucker rod string ll of Figure 1. The hydraulic unit may be secured directly to the walking beam 13 so as to reciprocate it, or directly to the sucker rod string itself. In a hydraulic pumping installation, pressure fluid would be supplied by a pump which would be driven by the motor ll;

The sensitivity of the present controller device 27 may be readily altered by changing its damping ratio and/or the spring constant. It is to be noted that when the present controller device 2? is adjusted so as to possess high sensitivity, it need not be mounted on a movable member of the pumping installation, as is the case with other well shut-off devices, but it may be mounted on any stationary member of the pumping installation, such as the Sampson post, well head, etc., which is subjected to abnormal vibrations generated by the well pump.

We claim as our invention:

1 A well pumping installation comprising a reciprocating well pump, a prime mover, transmission means connected between said prime mover and said pump for actuating said pump, an electric circuit energizing said prime mover, a controller for said circuit, said controller comprising a housing fixedly attached to said pumpmg installation, said housing having a cylindrical bore adapted to be filled with a fluid, switch means having at least one axially immovable contact element disposed in said bore, said switch means being connected to said circuit to close and open said circuit, a massive member slidably mounted in said bore for axial motion there: n, spring means urging said massive member into abutment with said axially immovable contact element, thereby maintaining said switch means normally closed during the operation of said prime mover, said massive member being impelled by the momentum imparted thereto by abnormal vibrations generated by the pump to move away from said stationary contact member, thereby opening said switch means and deenergizing the prime mover, passage means in said massive member permitting the transfer of the fluid in said bore from one side to the other of said member and check valve means in said passage means disposed to restrict said passage means to fluid flow during the spring responsive motion of the massive member.

2. A well-pumping installation actuated by a prime mover, said installation comprising a reciprocating well pump, transmission means connected between said prime mover and said pump for actuating said pump, an electric control circuit energizing said prime mover, and a controller device fixedly secured to said pumping installation and responsive to the abnormal vertical vibrations thereof, said controller device comprising switch means connected into said control circuit, spring-loaded movable weight means in contact with and normally closing said switch means, said weight means being displaced by abnormal vibrations generated by the well pump, thereby opening said switch means and de-energizing the prime mover.

3. A well-pumping installation actuated by a prime mover, said installation comprising a reciprocating well pump, transmission means connected between said prime mover and said pump for actuating said pump, an electric control circuit energizing said prime mover, and a controller device secured to said pumping installation and reciprocating therewith, said controller device being responsive to the abnormal vertical vibrations generated by said pump, said controller device comprising a tubular housing, a weight mounted for sliding movement in a substantially vertical plane within said housing, normally closed switch means carried within said housing above said weight and connected into said control circuit, and spring means carried within said housing for normally supporting said weight at its upper limit of travel against said switch means to maintain said switch means in a normally closed position, said switch means opening momentarily to de-energize said control circuit on downward displacement of the weight within said housing due to abnormal vibrations generated by said pump.

4. A well-pumping installation actuated by a prime mover, said installation comprising a reciprocating well pump, transmission means connected between said prime mover and said pump for actuating said pump, an electric control circuit energizing said prime mover, and a controller device secured to said pumping installation and reciprocating therewith, said controller device being responsive to the abnormal vertical vibrations generated by said pump, said controller device comprising a tubular housing, a weight mounted for sliding movement in a substantially vertical plane within said housing, damping means carried by said housing for damping the motion of said weight, normally closed switch means carried within said housing above said weight and connected into said control circuit, and spring means carried within said housing for normally supporting said weight at its upper limit of travel against said switch means to maintain said switch means in a normally closed position, said switch means opening momentarily to deenergize said control circuit on downward dis placement of the weight within said housing due to abnormal vibrations generated by said pump.

5. The well pumping installation of claim 4 wherein the transmission means comprises a string of sucker rods secured at the lower end to the well pump, a polished rod attached to the top of the sucker rod string, a pivotally mounted walking beam, clamp means securing said polished rod in a hinged manner to one end of said walking beam, a drive mechanism driven by said prime mover and a linkage arm connecting said drive mechanism to the other end of said walking beam, and wherein the controller device is mounted on the polished rod for reciprocation therewith.

6. The well pumping installation of claim 4 wherein the transmission means comprises a string of sucker rods secured at the lower end to the well pump, a polished rod attached to the top of the sucker rod string, a vertical-lift hydraulic reciprocating unit secured to the top of the polished rod and mounted over the well borehole, and pump means actuated by said prime mover means for supplying a pressure fluid to said hydraulic reciprocating unit, and wherein the controller device is mounted on the hydrauli reciprocating unit.

7. A well-pumping installation actuated by a prime mover, said installation comprising a reciprocating well pump, transmission means connected between said prime mover and said pump for actuating said pump, an electric control circuit energizing said prime mover, and a controller device secured to said pumping installation and reciprocating therewith, said controller device being responsive to the abnormal vertical vibrations generated by said pump, said controller device comprising a tubular housing having a cylindrical bore adapted to be filled with a fluid, a weight mounted for sliding movement in a substantially vertical plane within said housing, said weight being of slightly smaller diameter than the bore of said tubular housing whereby an annular fluid passageway is formed between said weight and said housing, a plurality of longitudinal fluid passageways extending vertically through said weight, said longitudinal passageways having a greater cross-sectional area than said annular passageway, check valve means in said longitudinal passageways closing said passageways to the downward flow of fluid therethrough, normally closed switch means carried within said housing above said weight and connected into said control circuit, and spring means carried within said housing for normally supporting said weight at its upper limit of travel against said switch means to maintain said switch means in a normally closed position, said switch means opening momentarily to de-energize said control circuit on downward displacement of the weight within said housing due to abnormal vibrations generated by said pump.

8. A well-pumping installation actuated by a prime mover, said installation comprising a reciprocating well pump, transmission means connected between said prime mover and said pump for actuating said pump, an electric control circuit energizing said prime mover, and a controller device secured to said pumping installation and reciprocating therewith, said controller device being responsive to the abnormal vertical vibrations generated by said pump, said controller device comprising a tubular housing having a cylindrical bore adapted to be filled with a fluid, a weight mounted for sliding movement in a substantially vertical plane within said housing, said Weight being of slightly smaller diameter than the bore of said tubular housing whereby an annular fluid passageway is formed between said weight and said housing, at least one fluid pas? sageway through said weight in communication between the spaces in the housing above and be: low said weight, said passageway having a greater cross-sectional area than said annular passage way, check valve means in said passageway os n Sa pa ewa to t e wnw rd o o fluid therethrough, normally closed switch means carried within said housing above said weight and connected into said control circuit, spring means carried within said housing for normally supporting said weight at its upper limit of travel against said switch means to maintain said switch means in a normally closed position, said switch means opening momentarily to de-energize said control circuit on downward displacement of the weight within said housing due to abnormal vibrations generated by said pump, and screw means extending through one wall of said housing for ad justing the tension of said spring.

9. A well pumping installation comprising a reciprocating-type pump positioned in a well borehole, a movable piston within said pump, a string or" sucker rods attached to said pump piston and extending to the surface of the borehole, linkage means secured to said sucker rod string, prime mover means positioned adjacent the wellhead and attached to said linkage means for reciprocating said linkage means and said sucker rod string in a vertical plane, a control circuit for energizing said prime mover means, and a controller device secured to said sucker rod string and reciprocating therewith, said controller comprising a housing, a weight slidably mounted for limited movement within said housing in a substantially vertical plane, spring means mounted within said housing for normally supporting said weight at its upper limit of travel, viscous damping means carried by said housing for damping the motion of said weight, normally closed switch means in said control circuit carried within said housing above said weight and normally in contact therewith, said switch means opening momentarily to de-energize said control circuit on downward displacement of the weight within said housing due to vibrations generated by said pump.

10. A well-pumping installation actuated by a prime mover, said installation comprising a piston-type reciprocating well pump, transmission means connected between said prime mover and said pump for actuating said pump, a control circuit for energizing said prime mover means, switch means for energizing said circuit a predetermined interval after the control circuit is deenergized, and a controller device secured to said pump reciprocating means for reciprocation therewith, said controller device comprising a tubular housing a Weight mounted for sliding movement in a substantially vertical plane within said housing, adjustable spring means carried within said housing for normally supporting said weight at its upper limit of travel thereby resetting said controller device after the control circuit has been de-energized, normally closed switch means carried within said housing above said weight and electrically connected in said control circuit, said switch means being closed when in contact with said weight at its upper limit of travel and opening momentarily to deenergize said control circuit on downward displacement of the weight within said housing when the fluid in the well has been pumped to the level of the well pump.

MARION V. LONG. FREDERICK CARL SCHNEIDER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,760,382 Teesdale May 27, 1930 2,260,312 Gruman Oct, 28, 1941 

